Electric rotating machine and manufacturing method of the same

ABSTRACT

A electric rotating machine includes a rotor winding constituting a part of a rotor, a conductor provided in a center portion in a radial direction of a rotor body for supplying electricity to the rotor winding from the outside, a leader drawn from the conductor to an outside diameter side, and a connecting line constructed by stacking a plurality of conductor plates to electrically connect the rotor winding and the leader. The connecting line consists of a radial direction linear portion which is straight in the radial direction on the leader side, and a bending portion which branches into two routes toward opposite directions to each other in a rotor shaft direction from the radial direction linear portion and has a linear portion formed at a part of the bending portion. The linear portion of the bending portion is joined to a bottom surface of the rotor winding.

This application is a divisional application of U.S. application Ser.No. 11/543,876, filed Oct. 6, 2006, now allowed.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an electric rotating machine and amanufacturing method thereof, and relates to an electric rotatingmachine such as a turbine generator and the like for example, which ispreferable for those provide with a connecting line which connects aconductor for supplying electricity from the outside and an end portionof a rotor winding, and a manufacturing method thereof.

2. Description of Related Art

A generator used in power generating equipment including a gas turbineor a steam turbine as a driving source generates electric power bymutual electromagnetic induction between a rotor and a stator. Ingeneral, a rotor winding is formed by a plurality of conductors woundthereon for producing an induction field, and a magnetic flux isgenerated by electrifying the winding. Accordingly, the rotor windingrequires a conductor for supplying electricity from the outside of thegenerator, and this conductor is generally provided in a center portionof a rotor body, and the conductor and an end portion of the rotorwinding are connected by a connecting line. The connecting line isgenerally designed to have a bending portion for the purpose ofrelieving deformation caused by the difference in thermal extension dueto the difference in material between the conductor and the rotor body,and by a centrifugal force (see U.S. Pat. No. 5,122,696, for example).

For the meantime, by technological advance in recent years, the size ofan electric rotating machine having the same output becomes more compactthan before, the output per unit volume increases, and correspondingly,the rise in temperature of a current-carrying part tends to be large.Therefore, it is the mainstream to apply an iron material to the rotorand apply a copper material to the rotor winding, however, the thermalextension difference caused by current applied during operation occursdue to the difference in physical properties between those.

Thus, in order to prevent each component member from breaking due tofatigue in strength, a mechanism for absorbing the thermal extension isrequired for applying it to an actual machine. Particularly, since agenerator of which the drive source is a gas turbine or a steam turbineis operated generally at 1500 to 3600 rpm in a steady state, a rotorhaving a rotary shaft of which the length is larger than its diameter isadopted in view of a limitation of strength due to a centrifugal force.Further, a rotor wining of the generator is often equipped with aconductor wound in a number of layers in a rectangular shape and has itslongitudinal direction in a rotor axial direction, and therefore, thethermal extension direction conspicuously appears in the axialdirection.

Further, for preventing the rotor winding from protruding in a radialdirection by its rotation, it is general to provide a rotor body partwith a wedge, and provide a rotor end portion with a retaining ring.However, since the retaining ring bellies out in the radial directionduring rotation due to a hoop force, the end portion of the rotorwinding located directly under there also bellies out toward an outsidediameter side in the same manner.

On the other hand, a conductor is provided in an axial center portion ofthe rotor and is connected with the external power supply forelectrifying the rotor winding, and a conductor support pillar attachedto this conductor and the end portion of the rotor winding areelectrically connected by a connecting line (lead). This connecting lineis repeatedly affected by the above described thermal extension in theaxial direction and by the displacement in the outside diameterdirection by a centrifugal force, at each actuation and stoppage.

As the structure which absorbs an operating force by this displacement,U.S. Pat. No. 5,122,696 proposes a connecting line which provides aspace by connecting two conductors having the structure of a T shapehaving a bent portion. Since a coil surface on which the connecting lineis mounted differs in radial direction position from another coilsurface, the structure of a main body of the connecting line forms the Tshape in order to absorb the displacement in the outside diameterdirection by a centrifugal force. The conductor at the bent portionspace of the T-shaped structure is constructed by a thin singleconductor, and has a second T-shaped conductor inside the abovedescribed T-shaped conductor in combination, for the purpose ofreinforcement.

BRIEF SUMMARY OF THE INVENTION

As described above, because the connecting line disclosed in U.S. Pat.No. 5,122,696 is has the shape which requires complicated assembleprocessing by using a single conductor which is not formed by stackingconductors, the connecting line is unfavorable in operability, and thespace occupation rate of a lateral bar portion of one of the abovedescribed T shapes is large, so that an insulating distance betweenadjacent coils which differ in electric potential becomes small, forexample. Further, since the connecting line has a vertical bar of theabove described T shape connected to the coil and the other one of theabove described T-shaped conductors in combination, the connecting lineitself becomes heavy, which makes the cause of the displacement in theaxial direction and the radial direction. In addition, if the coilsurface on which the connecting line is placed is close to the rotorsurface and therefor a space is small, it is difficult to install thiscomplicated structure.

A first object of the present invention is to provide an electricrotating machine having a connecting line which is easily mounted withsimple structure and favorable in operability, secures an insulatingdistance from an adjacent coil, absorbs thermal extension in an axialdirection repeatedly occurring at each actuation and stoppage and anoperating force caused by displacement in a radial direction due to acentrifugal force, and does not lead to a fatigue fracture.

Further, a second object of the present invention is to provide amanufacturing method of an electric rotating machine which suppressestemperature rise of a bending portion of a connecting line to preventreduction in strength of a copper material of the connecting line, whenconnecting the connecting line in the electric rotating machine.

In order to attain the above described first object, an electricrotating machine of the present invention includes a rotor windingconstituting a part of a rotor, a conductor provided in a rotor body forsupplying electricity to the rotor winding from the outside, a leaderdrawn from the conductor, and a connecting line constructed by stackinga plurality of conductor plates to electrically connect the rotorwinding and the leader, characterized in that the connecting linecomprises a radial direction linear portion which is straight in aradial direction on the leader side, and a bending portion whichbranches off into two routes toward opposite directions to each other ina rotor shaft direction from the radial direction linear portion and hasa linear portion formed at a part of the bending portion, and the linearportion of the bending portion and a bottom surface of the rotor windingare joined to each other.

In addition, in order to attain the second object, a method ofmanufacturing an electric rotating machine of the present invention ischaracterized in that when connecting a rotor winding constituting apart of a rotor and a leader line drawn to an outer diameter side from aconductor provided in a center portion in a radial direction of a rotorbody for supplying electricity to the rotor winding from the outside,via a connecting line which is constructed by stacking a plurality ofconductor plates and comprises a radial direction linear portion whichis straight in the radial direction on the leader line side and abending portion branching off into two routes toward opposite directionsto each other in a rotor shaft direction from the radial directionlinear portion and having a linear portion formed in a part of thebending portion, by electrically joining the linear portion of thebending portion and a bottom surface of the rotor winding, a coolingstructure is inserted in a hollow part formed in the bending portion ofthe connecting line, a brazing material is subsequently sandwichedbetween the bottom surface of the rotor winding and the connecting lineof the bending portion, a brazing material flow inhibitor is applied onthe bending portion of the connecting line, and the brazing material issubsequently heated and melted while flowing a cooling medium in thecooling structure to join an outermost layer of the conductor plates andthe bottom surface of the rotor winding.

According to the present invention, since the connecting line having thebending portion, and the bottom surface of the rotor winding only haveto be joined to each other, it is unnecessary to use an extra componentor perform an extra attachment operation like the prior art, and it ispossible to receive a centrifugal force by the bottom surface of therotor winding. Further, since deformation in the axial direction and theradial direction can be absorbed by the bending portion of theconnecting line, it becomes possible to absorb thermal extension in theaxial direction repeatedly occurring at each actuation and stoppage ofthe electric rotating machine, and an operating force caused bydisplacement in the radial direction due to a centrifugal force. As aresult, the deformation amount of the connecting line is suppressed, anda fatigue fracture is prevented.

In addition, according to the manufacturing method of the presentinvention, since it is possible to suppress temperature rise of thebending portion of the connecting line when connecting the connectingline in the electric rotating machine, reduction in strength of thecopper material of the connecting line can be prevented.

Other objects, features and advantages of the invention will becomeapparent from the following description of the embodiments of theinvention taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 shows one example of an electric rotating machine of the presentinvention, and is a partial sectional view of a rotor end portion;

FIG. 2 shows another example of the electric rotating machine of thepresent invention, and is a partial sectional view of a rotor endportion;

FIG. 3 shows another example of the electric rotating machine of thepresent invention, and is a partial sectional view of a rotor endportion;

FIG. 4 shows another example of the electric rotating machine of thepresent invention, and is a partial sectional view of a rotor endportion;

FIG. 5 shows another example of the electric rotating machine of thepresent invention, and is a partial sectional view of a rotor endportion;

FIG. 6 shows another example of the electric rotating machine of thepresent invention, and is a partial sectional view of a rotor endportion;

FIG. 7 shows one example of an electric rotating machine manufacturingmethod of the present invention, and is a view corresponding to aconnecting line shown in FIG. 1;

FIG. 8 is a view showing one example of the electric rotating machine;and

FIG. 9 is a perspective view showing one example of a rotor in FIG. 8.

DETAILED DESCRIPTION OF THE INVENTION

A connecting line which absorbs thermal extension in an axial directionwhich repeatedly occurs at each actuation and stoppage, and an operatingforce caused by displacement in a radial direction due to a centrifugalforce, and does not lead to a fatigue fracture is realized with simplestructure which is easily mountable and has favorable operability.

Example 1

Hereinafter, a connecting line in an electric rotating machine accordingto an embodiment of the present invention will be described withreference to the drawings.

FIG. 8 shows a turbine generator as one example of the electric rotatingmachine, and the turbine generator is generally constructed by a rotor 1which is formed by winding a rotor winding (not shown) on a rotor bodypart 1 b fixed to a rotary shaft 1 a, and a rotor 20 which is formed bywinding a stator winding 20 c on a stator core 20 b fixed to a statorframe 20 a.

FIG. 9 shows the rotor 1 of the turbine generator shown in FIG. 8. Asshown in the drawing, the rotor 1 is constructed by the rotary shaft 1 aand the rotor body part 1 b which is fixed to the rotary shaft 1 a andextends in an axial direction, and has a plurality of slots formed witha predetermined space in a circumferential direction from each other, arotor winding 2 with a plurality of rotor conductors stacked and housedin the respective slots of the rotor body part 1 b, a retaining ring(holding ring) 4 which covers and holds an end portion of the rotorwinding 2 in the axial direction, and a wedge 3 provided on a surfacefor preventing the rotor winding 2 inside the slot of the rotor bodypart 1 b from dropping out.

Next, the connecting line in the electric rotating machine of thepresent invention described above will be described by using FIG. 1. Asshown in FIG. 1, the connecting line (lead) 10 is used for electricallyconnecting a conductor support pillar (stud) 6 which is a leader forleading in a radial direction from a conductor in the axial centerportion of the rotor 1, and an end portion of the rotor winding 2.

The connecting line 10 constructed by stacking a plurality of conductorplates is generally constructed by a radial direction linear portion 10b which extends in the radial direction from the conductor supportpillar 6 which is the leader located in the center portion of the rotor1, and a bending portion 10 a which branches off into two routes fromthe radial direction linear portion 10 b. The radial direction linearportion 10 b is provided with a stopper 12 for tying the stackedconductor plates, on the boarder of the bending portion 10 a.

Further, the connecting line 10 is joined to a bottom surface of therotor winding at an outermost layer plane portion of an axial directionlinear portion 10 d of the bending portion 10 a.

The bending portion 10 a is formed by portions 10 e parallel with therotor shaft which branch off from a root portion 10 c of the connectingline into two routes in the directions opposite from each other in therotor shaft direction with the same number (three in the drawing) ofconductor plates for each route, a curve portion 10 f which extends fromeach of tip ends of the portions 10 e parallel with the rotor shaft andis formed into a U-shape, and the axial direction linear portion 10 dwhich extends inward the rotor shaft direction from each of tip ends ofthe curve portions 10 f, and forms bilateral symmetry with respect to acenter line of the radial direction linear portion 10 b to construct onespace.

By constructing it in this manner, a centrifugal force of the connectingline 10 itself, which is applied in the radial direction (and acts inthe upper direction in the drawing) when the electric rotating machinerotates, becomes ultimately applied to the entire bottom surface of therotor winding. In this example, since the connecting line branches offto be bilaterally symmetrical in the rotor shaft direction, the abovedescribed centrifugal force is dispersed equally to the two routes, andthus is absorbed and relieved by the bending portion 10 a forming acurved surface.

Further, the thermal extension deformation in the axial direction (thelateral direction in the drawing) can be absorbed by the curve portions10 f of the bending portion 10 a of the connecting line, and by theradial direction linear portion 10 b having the cantilever structure.

Accordingly, by further adding the above described structure to theconnecting line constructed by stacking a plurality of conductor plates,it is possible to absorb the thermal extension in the axial directionwhich repeatedly occurs at each actuation and stoppage, and theoperating force caused by the displacement in the radial direction dueto the centrifugal force, and becomes possible to suppress thedeformation amount of the connecting line to prevent the fatiguefracture.

The stopper 12 can prevent the radial direction linear portion 10 b ofthe connecting line from opening by the centrifugal force.

Other examples of the present invention will be shown in FIGS. 2 to 6.

FIGS. 2, 3 and 4 show the other examples of the present invention inwhich the connecting line 10 branches off into two laterally symmetricalroutes in both directions of the rotor shaft, and FIGS. 5 and 6 showother examples of the present invention in which the connecting line 10branches off into two laterally unsymmetrical routes in both thedirections of the rotor shaft.

Example 2

FIG. 2 shows an example in which the stopper 12 in the example shown inFIG. 1 is not provided, and all other components are the same as thosein the example shown in FIG. 1.

In this example, although it is impossible to prevent the radialdirection linear portion 10 b of the connecting line from opening by thecentrifugal force, it is possible not only to provide the effects of theabove described example, but also to somewhat relieve the displacementin the outside diameter direction due to the centrifugal force acting onthe connecting line 10 by the amount of the mass of the stopper 12 beingeliminated.

Example 3

FIG. 3 shows an example in which the shape is made into a substantiallyinverted triangle by possibly shortening the bending portion 10 a of theconnecting line in the example shown in FIG. 2.

The bending portion 10 a is formed into a triangular shape by a linearportion 10 i in which the conductor plates extend in a V shape statefrom the radial direction linear portion 10 b to branch into two routeswith the same number (three in the drawing) of the conductor plates foreach route, and by an axial direction linear portion 10 d in which eachof tip ends of the linear portion 10 i extends inward in the rotor shaftdirection via arc portions 10 h to define one space.

In this example, it is possible not only to achieve the same effect asthe above described example, but also to reduce the centrifugal forceitself due to the own weight by making the mass of the connecting line10 as small as possible, and therefore, the displacement in the outsidediameter direction can be relieved. This example is effective when thedistance between the conductor support pillar 6 and the rotor winding 2is short due to the structure of the electric rotating machine.

Example 4

FIG. 4 shows an example in which the shape of the bending portion 10 aof the connecting line in the example shown in FIG. 2 is made into asubstantially quadrangle.

The bending portion 10 a is formed into the quadrangle by a portion 10 eparallel with the rotor shaft in which the conductor plates branch offfrom the radial direction linear portion 10 b into two routes with thesame number of the conductor plates (three in the drawing) for eachroute in the directions opposite to each other in the rotor shaftdirection, a linear portion 10 i which extends in the radial directionvia an arc portion 10 g from each of the tip ends of the portions 10 ewhich is parallel with the rotor shaft, and is parallel with the radialdirection linear portion 10 b, and an axial direction linear portion 10d which extends inward in the rotor shaft direction via arc portions 10h from each of the tip ends of the linear portions 10 i parallel withthe radial direction linear portion 10 b, and defines one space.

In this example, it is possible not only to achieve the same effect asthe above described example, but also to absorb the deformation by thethermal extension in the axial direction of the rotor to a large extentsince the shape of the connecting line has a soft structure flexible inthe lateral direction by making the shape of the bending portion 10 a ofthe connecting line closer to a quadrangle. This example is effectivewhen the distance between the conductor support pillar 6 and the rotorwinding 2 is large due to the structure of the electric rotatingmachine.

Example 5

FIG. 5 shows an example in which the connecting lines 10 of the exampleshown in FIG. 2 and the example shown in FIG. 3 are combined in shape.That is, the bending portion 10 a of the connecting line forms a shapemade by integrating the right half of the curve portion of the bendingportion 10 a of the connecting line shown in the example of FIG. 2, andthe left half of the inverted triangle of the bending portion 10 a ofthe connecting line shown in the example in FIG. 3.

In this example, it is possible not only to achieve the same effect asin the above described examples, but also to reduce the own weight asmuch as possible and to absorb the centrifugal force by the curveportion as a result that the mass of the connecting line 10 is reducedas much as possible and one side of the bending portion 10 a of theconnecting line forms the curve portion, though the connecting line isbilaterally unsymmetrical in both directions of the rotor axis, and thecentrifugal force by rotation is unevenly dispersed to the two routes,and therefore, the operating force by the displacement in the radialdirection due to the centrifugal force can be relieved. This example iseffective when the connecting line 10 cannot adopt the bilateralsymmetrical shape due to the structure of the electric rotating machine.

Example 6

FIG. 6 shows an example which forms a shape in which the connecting line10 of the example shown in FIG. 5 is laterally inverted in the axialdirection. That is, the bending portion 10 a of the connecting lineforms a shape made by integrating the left half of the curve portion ofthe bending portion 10 a of the connecting line shown in the example ofFIG. 2, and the right half of the inverted triangle of the bendingportion 10 a of the connecting line shown in the example of FIG. 3.

In this example, it is possible not only to achieve the same effect asin the above described example, but alto to sufficiently keep electricalinsulation since the right side of the bending portion 10 a of theconnecting line forms the shape of the inverted triangle and thereby thedistance 11 between an adjacent rotor winding 2 b and the connectingline 10 is secured.

The present invention is not limited to the examples shown in the abovedrawings, but for example, the stopper 12 can be used in FIGS. 3 to 6.

Example 7

Next, an example of joining the connecting line 10 to the rotor winding2 at the time of manufacturing the electric rotating machine of thepresent invention will be shown in FIG. 7.

Usually, a member mainly made of copper is used for the connecting line10, a brazing material (a metal joining material) 13 is used for joiningthe connecting line 10 to the rotor winding 2 at the time ofmanufacturing the electric rotating machine. At the time of the joint,the brazing material 13 is melted with high heat, and therefore, thehigh heat is conducted to the connecting line 10. However, the coppermaterial is known to change in its material properties and reduce(soften) in strength of the copper material when it is exposed to thehigh temperature. Accordingly, it is necessary to prevent the heat frombeing conducted to the connecting line 10 which receives stressrepeatedly at each actuation and stoppage of the electric rotatingmachine, especially to the bending portion 10 a of the connecting line,as much as possible at the time of joining it to the rotor winding 2.

In the present invention, the brazing material 13 is provided betweenthe stacked layers of the connecting line 10 which is constructed bystacking a plurality of conductor plates, and between the connectingline 10 and the stopper 12 to join those with each other in advance, andthen the connecting line 10 is joined to the conductor support pillar 6.Thereafter, a cooling structure 14 having a cooling water tube 15 isinserted into a hollow part 17 of the connecting line enclosed by thebending portion 10 a of the connecting line, the planar brazing material13 is sandwiched between a connecting portion 2 a of the rotor windingand the connecting line 10, and a brazing material flow-inhibitor 16 iscoated on the bending portion 10 a of the connecting line. After thepreparation of theoe, the brazing material 13 is melted by inductionheating or the like (not shown) while flowing the cooling water in thecooling water tube 15, and a plane portion of the outermost layer of theconductor plate of the connecting line 10 and the bottom surface of therotor winding 2 are joined.

According to the method of the present invention for joining theconnecting line 10 to the rotor winding 2 as shown above, since thebrazing material flow-inhibitor 16 is coated on the bending portion 10 aof the connecting line, the high-temperature molten brazing material 13can be prevented from flowing into the bending portion 10 a of theconnecting line. Further, by the cooling water flowing in the coolingwater tube 15, the heat conduction to the bending portion 10 a of theconnecting line is absorbed and the temperature rise can be suppressed.As a result, reduction in strength of the copper material of theconnecting line 10 can be prevented.

The electric rotating machine having the connecting line according tothe present invention can be applied to a generator including a gasturbine or a steam turbine as a drive source, or an electric motor.

It should be further understood by those skilled in the art thatalthough the foregoing description has been made on embodiments of theinvention, the invention is not limited thereto and various changes andmodifications may be made without departing from the spirit of theinvention and the scope of the appended claims.

1.-8. (canceled)
 9. A method of manufacturing an electric rotatingmachine, including the steps of connecting a rotor winding constitutinga part of a rotor and a leader line drawn to an outer diameter side froma conductor provided in a center portion in a radial direction of arotor body for supplying electricity to the rotor winding from theoutside, via a connecting line which is constructed by stacking aplurality of conductor plates and comprises a radial direction linearportion which is straight in the radial direction on the leader lineside and a bending portion branching off into two routes toward oppositedirections to each other in a rotor shaft direction from the radialdirection linear portion and having a linear portion formed in a part ofthe bending portion, by electrically joining the linear portion of thebending portion and a bottom surface of the rotor winding, theconnecting step including: inserting a cooling structure in a hollowpart formed in the bending portion of the connecting line; subsequently,sandwiching a brazing material between the bottom surface of the rotorwinding and the connecting line of the bending portion, and applying abrazing material flow inhibitor on the bending portion of the connectingline; and subsequently, heating the brazing material to melt the brazingmaterial while flowing a cooling medium in the cooling structure, tojoin an outermost layer of the conductor plates and the bottom surfaceof the rotor winding.
 10. The method of manufacturing the electricrotating machine according to claim 9, wherein the cooling structurecomprises a cooling water tube in which cooling water flows.